Most prior release agents used on tape have failed because they have a low softening point. For instance, when paraffin wax is applied directly to tape as a release coating or when it is applied as an emulsion that leaves a coating of wax, a product that cannot withstand high temperature storage may be produced. The wax softens and flows so that an effective release coat is no longer present between layers of the tape. In addition, conventional release agents have tended to migrate into the adjoining adhesive layer with the result that adhesiveness and tack are lost in storage and the tape is unusable.
Conventional silicone base release agents have also been unsatisfactory. In addition to their high cost, some of these agents cause loss of adhesion and tack upon aging that results from the tape being exposed to high temperature and/or high humidity.
Moisture has likewise deleteriously affected the release agent while the tape is stored with the result that high unwind forces may be required or a loss of adhesiveness in the tape may be encountered.